Method and apparatus for manufacturing fibrous structures



Nov. 10, 1970 w. c. TRETHEWEY METHOD AND APPARATUS FOR MANFACTURING FIBROUS STRUCTURES 5 Sheets-$heet 1 Filed July 25. 1967 Jami 6U wi a mi Q 255m SQIQDQ CQ ATTORNEYS METHOD AND APPARATUS FOR MANFACTURING FIBROUS STRUCTURES Filed July 25. 1967 Nov. 10, 1970 w. c. TRETHEWEY 3 Sheets-Sheet 2 W/AAM/Wf y QMMMA AT'IORNEYS Nov. 10,

W. C. TRETHEWEY METHOD AND APPARATUS FOR MANFACTURING FIBROUS STRUCTURES Filed July 25, 1967 3 Sheets-Sheet :5

[wk [I Z5 MASTER SONTR0E EI//UZ@ THROUGH-PUT K SENSING III HOOD WIDTH CONTROL 5.5 $3 54; :1 E BINDER EEE i I [6/ CONTROL D IIRITIINETIc ,I L I cIRcIIIT E M E S-.SE S E 4 5 I '3 4 5; :CONVEY JR S EED- 657 CO T *ETINPIIRISON E E 75 ::I CIRCUIT ALARM I... ITELE R ENIEIE I X-RAY 6367 SENSING i g W oI/EN BLOWER M M. CONTROL TRIM SAW CONTROL v 6@ E I\ CHOPPER CYCLE L CONTROL WW. w 65 cOMRRESSION CONTROL ATTORNEYS United States Patent Oflice 3,539,316 Patented Nov. 10, 1970 3,539,316 METHOD AND APPARATUS FOR MANUFAC- TURING FIBROUS STRUCTURES William C. Trethewey, Newark, Ohio, assignor to Owens- Corning Fiberglas Corporation, a corporation of Delaware Fiied July 25, 1967, Ser. No. 655,942 Int. Cl. C03b 37/02 US. Cl. 65-2 15 Claims ABSTRACT OF THE DISCLOSURE The embodiment described herein comprises apparatus for forming a fibrous structure which comprises a fiber deposition station which includes a movable collecting surface and means for providing fibers above the collecting surface for deposition on the surface. An additional component such as a binder, may be added to the fibers on the surface. Further treatment of the binder and fibers may include heating and curing. The fibrous structure then may be edge trimmed, chopped to a desired length and packaged. Each of the functions of the apparatus may be controlled by a master control to set the variables for the type of product to be manufactured. Some of the functions are interrelated so that a change in one of the variables produces a change in the remaining functions down the line. For example, the rate of deposition of the fibers on the collecting surface may be sensed and utilized to control one or more of the remaining functions of the fibrous structure production line.

As the instrumentation approach in measurement and control of variables, apparatus and processes has grown more sophisticated, it has become possible to completely automate various production lines so that better quality and more quantity may result. However, in production processes where variables are interrelated and Where the interrelation changes when a different type of the same product is produced on the same production line it is necessary to solve a number of problems in order to satisfactorily relinquish control of the production line to instrumentation. For example, where a production line is to be adapted for a large number of fibrous structure products of different densities, widths, and lengths, not only must the important variables be adjust when starting to make each difierent product but it is necessary to interrelate variables in order to insure that quality of the product is maintained and improved as Well as improving the efficiency of the production line output.

Accordingly, it is an object of this invention provide an improved method and apparatus for forming fibrous structures.

It is a further object of this invention to provide an improved method and apparatus for forming fibrous structures which includes means for interrelating the variables in the production to maintain an improved quality while increasing quantity of output.

A still further object of this invention is to provide an improved production line adapted to manufacture a large number of fibrous structures, each having different densities, widths, lengths, etc.

An additional object of this invention is to provide a production line in which the variables for each of a number of products may be adjusted by a master control, which variables may then be maintained in the proper interrelationship.

In accordance with the above objects this invention features apparatus for forming a fibrous structure which comprises a fiber deposition station which includes a movable collecting surface means and means for providing fibers above the collecting surface means for deposition thereon. Means are utilized to sense the rate of deposition of fibers on the collecting surface and provide a signal proportional thereto. The fiber providing means may include means for melting heat-softenable material and means for attenuating fibers from the molten material. The rate of deposition sensing means may include means for monitoring heat supplied to the material to maintain the material at a predetermined attenuating temperature.

The signal obtained from the rate of deposition of fibers on the collecting surface may be utilized to interrelate the remaining variables in the process or production line. Means for driving the collecting surface past the fiber deposition station may be made responsive to the rate of deposition signal to hold the speed of the collecting surface at a rate proportional to the rate of deposition sensed. Further, means for supplying an additional component such as a binder to the fiber structure being formed may be made responsive to the deposition rate signal to supply the additional component in an amount proportional to the rate of deposition sensed. If the binder is to be heated and/ or cured the amount of heat supplied for the heating and curing may be made proportional to the deposition rate of fibers. If the heating means includes means for circulating a gas through the mass of binder and fibers and means for heating the gas, the gas circulation means may be made responsive to the rate of deposition sensing to circulate a volume of gas through the mass proportional to the rate of deposition sensed.

To provide a check on the interrelation of the variables, means such as an X-ray sensing means may be utilized for measuring the weight per unit area of the fibers and/ or binder deposited on the collecting surface and provide a measurement signal proportional thereto. This measurement signal may be compared with the rate of deposition signal to check the accuracy of the rate of deposition signal. In response to a predetermined difference between the actual and predicted quantities a difference signal may be provided for activating an alarm means, modifying the effert of the rate of deposition signal on the collecting surface driving means, modifying the effect of the rate of deposition signal on the additional components or binder supplying means, and modifying the effect of the rate of deposition signal on the heating and curing means.

While a primary variable such as the rate of the deposition of fibers on the collecting surface may be utilized to directly control the remainder of the interrelated variables, method and apparatus is also shown for maintaining the proper relationships between other variables, whether or not the other variables are also directly or indirectly controlled by the primary variable being sensed. These relationships may be used to directly alter or to modify the controls for the variables. For example, the speed of the collecting surface means may be utilized to control the heating and curing of the binder by supplying an amount of heat proportional to the speed of the collecting surface. If the heating means includes gas circulating means, the volume of gas circulated may be made proportional to the speed of the collecting surface means through an oven. Means for separating or chopping a continuous strip of the fibrous structure being formed on the movable collecting surface may be made responsive to the speed of the collecting surface to insure that the individual lengths are of the proper dimensions.

As noted hereinbefore a master control means may be utilized which is adapted to provide a signal to set the various individual controls at settings calculated to produce a predetermined product having a desired density, width, length, etc. To insure that the equality of the product remains uniform the set points thus activated on the various individual controls then may be subject to modification by the sensing of one of the variables to insure that the proper interrelationships of the variables is maintained.

The invention further features a method of manufacturing a fibrous mat which comprises the steps of moving a collecting surface past a fiber providing station, depositing fibers thereon, sensing the rate of deposition of fibers on the collecting surface and varying the speed of the collecting surface in response to the rate of deposition sensed to obtain a mat-like mass of fibers on said collecting surface having a desired thickness or weight per unit area. The method may include the further step of adding binder in the mat-like mass in an amount proportional to the sensed rate of deposition of fibers. A hood may be positioned between the fiber providing station and the collecting surface and the side walls of the hood adjusted to define the width of fiber deposition on the collecting surface. The speed of the collecting surface may be varied in response to the sensed rate of deposition and the adjusted hood width to obtain the desired thickness of fiber deposition. The method may further include a step of heating the binder to effect a cure thereof and controlling the amount of heat supplied in response to the thickness of the mass, the amount of binder added, or the speed of the collecting surface. In the method all of the variables may be provided with an individual set point of predicted operation, which variables may be adjusted in response to the sensing of a primary variable in order to maintain the proper interrelationships.

Other objects, advantages and features of this invention will become apparent when the following description is taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a semidiagrammatic view of a production line embodying the teachings of this invention;

FIG. 2 is a view in perspective of an adjustable hood to control fiber deposition widths; and

FIG. 3 is a block diagram of control circuitry for the production line illustrated in FIG. 1, which controls embody the teachings of this invention.

Referring to FIG. 1 there is illustrated a production line for the manufacturing of fibrous structures such as insulating Wool mats, bats or the like. A molten heatsoftenable material such as glass may be supplied by a forehearth to a feeder or bushing structure 11 having tipped orifices 12 formed in the bottom thereof to provide streams of the molten material for attenuation into fibers. Electrical terminals 14 on each end of the feeder or bushing 11 are connected via power lines 15 and 16 to a bushing power supply and control 20. The control 20 is operative to supply current to the terminals 14 which is translated into heat flowing through the bushing or feeder 11 in an amount sufiicient to maintain the molten material within feeder 11 at a desired or predetermined attenuating temperature.

While other attenuating means may be utilized there is shown herein a blower 13 for directing gaseous blasts of steam or other gases at the streams issuing from orifices 12 to attenuate the streams into fibers which are received by a movable collecting surface means generally indicated at 40. The movable collecting surface means 40 in this instance comprises an endless belt 41, preferably of a foraminous material so that a suction may be applied beneath the belt to attract the fibers to the belt and hold them in their deposited position, mounted on conveyor rollers which are driven by conveyor drive means 42.

A hood or shield means is generally indicated at which is adapted to confine the deposition of the attenuated fibers over a predetermined area. Referring to FIG. 2 it will be seen that the hood means 30 comprises a front wall 31, a rear wall 32, and side walls 33, 34. Side walls 33 and 34 are each connected via one or more arms 35 to a width control mechanism 36. Side walls 33 and 34 may thus be moved inwardly and outwardly to determine the Width of deposition of fibers on the collecting surface of the conveyor belt 41. The width adjustment control 36 may comprise a suitable mechanical linkage, e.g. a rack and pinion arrangement driven by a motor means which is responsive to a signal from a master control to set the side walls 33 and 34 at the desired Width.

One or more binder dispensing means are disposed to dispense a binder or other additional component in the fibers being collected on conveyor 41. The binder dispensing means may be connected via a flow control means such as valve 51 to a supply of binder 52. The flow of binder through the valve 51 may be electrically controlled by binder feeder control 53. Although the additional component being supplied to the fibrous mass deposited on the conveyor surface 41 is shown in the drawings as binder it should be noted that other components may be added to the mat in addition to or instead of a binder. For example, if the mat being formed is to be utilized in filter applications it may be desirable to intersperse in the mat a collecting compound such as an oil which will cause dust or dirt particles in the air to adhere to the otherwise relatively smooth glass fibers which are integrated into a filter mat.

Means for measuring the actual deposition in terms of weight per unit area may be provided for checking, comparing and sounding an alarm, if a tolerance is exceeded, or modifying one or more of the variables involved. An X-ray sensing means is suitable for such a purpose. When a beam of X-rays is shot through the mat-like mass of fibers a measuring device indicates how much X-radiation is absorbed. Thus the X-ray sensing means may be set to measure the quantity of fiber per unit area and/or the quantity of hinder or additional component with the fibers in the mat-like mass on the collecting conveyor 41.

In the manufacture of a majority of the fibrous structures or mats compression to some degree is desirable or necessary. Accordingly, compression roller means 66 is illustrated which is operative to compress the mat-like mass to the desired thickness. The compresion roller means is controlled by compression control 66 to adjust the compression to the amount desired. Compression of the mat or other structure may occur prior to or during a curing process for the binder or both.

An oven means 70 is illustrated for curing the binder or otherwise heat treating the additional component added via dispenser 50. Ducts 71 and 72 are connected to circulate a gas, usually air, through foraminous oven conveyors and thus through the combined mass of binder and fibers. If heat is desired the air or gas being circulated is heated by heaters 74 controlled by a heater control 75 which is responsive to a thermocouple or other heat sensing means 76 disposed within the oven 70. An oven blower drive 73 controls the amount of air being circulated through the fibrous structure.

It is desirable in some instances to trim the edges of the fibrous structure either to a desired width or to remove rough edges to present a smooth appearance. Accordingly, trim saw means 80 is illustrated for accomplishing the trimming, the width and speed of the trim being under the control of the trim saw control 81. A chopper means is provided to separate or cut the continuous fibrous structure into the desired lengths. The cycle of the chopper is controlled by the chopper control 86. The fibrous structure is then packaged for shipment at the packaging station in a variety of ways depending upon the structure being formed.

Referring to FIG. 3 there is illustrated in block diagram form a control circuit embodying the teachings of this invention as applicable to the apparatus illustrated in FIG. 1. A master control means 100, such as a computer, is adapted to receive an input in the form of a punched card which may be placed in slot 102 and read in the usual manner, by manual settings chosen and programmed into the machine such as by setting control dials or knobs 101, or in any other suitable way such as electromagnetic tape or other devices for reading in a setting to a control. The input to the master control provides information as to the width, thickness, density, type of binder, curing information, and other information for variables as required to make the desired product. The master control may be adapted to provide an output signal along lead 100a to provide a set point for each of the variables involved which has been precalculated to be the probable point of operation of each variable. In some instances there is no modification of the set point provided by the master control. For example, the set point which is received by the hood width control 36 will seldom require modification of the adjustment means 36 for the walls 33 and 34 of the hood 30 is properly calibrated. Similarly, it is unlikely that the compression control 66 or the trim saw control 81 will require modification once in operation. Other variables, however, are interrelated and if one variable should change arrangements should be made to effect a corresponding change in other interrelated variables.

In a production line as illustrated in FIG. 1 the primary variable in most instances will be the throughput of the feeder-attenuating mechanism which will result in a particular rate of deposition of fibers upon the collecting surface 41. Thus the remaining variables such as the binder feed control 53, the conveyor feed control 45, the oven heater control 75, the oven blower control 73 and the chopper cycle 86 receive their initial set points on lead 100a from the master control 100, which set points are precalculated on the basis of a predicted through-put or rate of deposition of fibers on the collecting surface 41.

Assuming that there is no alteration in the primary variable the operation will proceed on the basis of the preselected settings provided by the master control 100. That is, a predetermined through-put of fibers or rate of deposition of fibers on the collecting surface 41 will require the preselected amount of binder or additional component to be added by dispenser 50. Further, the collecting surface will be driven past the fiber deposition station at a rate of speed preselected by and set into the conveyor speed control. The oven heater control 75 will insure tha the preselected amount of heat will be furnished by heaters 74 and that the air so heated will be circulated at a volume as preselected and set into the oven blower drive 73. Since the speed of the conveyor or collecting surface will not be varied, the cycle of the chopper control to provide the predetermined lengths will remain as preselected and set into the chopper control 86.

However, if the primary variable does change for some reason during the process of production it will be necessary to effect a corresponding change in the interrelated variables in order to maintain the quality desired.

In the apparatus illustrated in FIG. 1 the rate of deposition is the chosen primary variable. Although other suitable ways must be used to sense the rate of deposition it is preferable in this instance to gain an indication of output from a melting unit by monitoring the power input to the feeder or bushing 11 via leads 15 and 16 necessary to maintain the molten material at a predetermined attenuating temperature. In this instance, the power into the bushing is indicative of the amount of glass flowing therefrom. Therefore the through-put sensing device 25 monitors the power supplied to the bushing and provides a signal which is proportional to the rate of deposition of the fibers on the collecting surface 41. Referring to FIG. 3, the proportional signal may be fed via lead 25a to the interrelated variables to modify their action if the sensed rate of deposition varies from the predicted rate of deposition as set into the interrelated variables by the master control 100. It should be noted that the rate of deposition signal could be utilized by itself to control the remaining interrelated variables and is considered to be one of the novel parts of this invention. However, by using a master control 100 to preselect set points for each of the interrelated variables it is easier to obtain a more accurate control since a large scale for closer control can be utilized for each variable within a predetermined range as selected by the master control. This enables the utilization of a larger range close to the set point afiFording more accuracy in the control of the quality of the product.

Assume that there has been an upset in the through-put or rate of deposition during the operation of the process, for example, a relatively large change in the temperature of the glass or other heat-softenable material being fed to the feeder or bushing 11 from the forehearth 10, thus making a change in the rate of deposition on the collecting surface 41. The change in the proportional signal supplied on lead 25:: would thus modify the effect of the master control signal on the binder feed control to provide a change in the amount of binder supplied to match that of the new rate of deposition. The change in the proportional signal would be sensed by the conveyor speed control 45 to change the speed of the collecting surface 41 past the deposition station so that the desired thickness is maintained. The rate of deposition change would also be sensed by the over heater control 75 and the oven blower control 73 to make the necessary heating and air circulation changes necessary for the new rate of deposition and thus the new line speed or collecting surface speed through the heating and curing means 70. Finally, the cycle of the chopper would be changed to that which corresponds to the new line speed and rate of deposition as sensed by the chopper cycle control 86.

In the preceding paragraph the change in the primary variable was utilized to directly effect a corresponding change in each of the other interrelated variables. However, it may be desirable in some instances to provide an interconnection between the variables other than the primary variable to either effect the changes or to check the change to see if it was accurate. For example, the output from the binder feed control 53 along lead 53a may be sampled and fed to the conveyor speed control 45 to provide a check or to elfect the change by itself. Similarly, the sampling of the binder feed control 53 output on lead 53a may be utilized to check or effect the change by itself in the oven heater control 75 and the oven blower control 73.

In another example illustrated in FIG. 3 the output of the conveyor speed control 45 on lead 45a may be sampled to check or efiect a change in the binder feed control 53, the oven heater control 75, the oven blower control 73, and/or the chopper cycle control 86.

On some products it is desirable to maintain an actual physical check on the performance of the interrelated variables. This may be provided by the X-ray sensing unit or means 60. As indicated hereinbefore the X-ray sensing unit may be utilized as a double check to assure that the proper density will result when the compression of the material is accomplished before and/or during cure. The X-ray unit 60 observes the fibers and/or binder on the collecting surface 41 to determine whether the quantity of fibers per unit area is proper for the thickness to be produced. The signal resulting from this sensing may be fed through lead 60a to a comparison circuit 62. The comparison circuit may receive a signal from the master control corresponding to the desired weight per unit area. If in comparing the signal from lead 100a and 60a, a difference beyond a tolerance is observed a difference signal may be provided on lead 62a to activate an alarm circuit 63.

As an alternative comparison a signal proportional to the through-put or rate of deposition as received from lead 250, a signal proportional to the amount of binder being supplied as received from lead 53a, and/or a signal proportional to the line speed or collecting surface speed may be received from lead 45a by the arithmetic circuit 61. The signals can be used alone or in any combination to provide an output on lead 61a which is a measure of or is proportional to the quantity of fibers being deposited per unit area (by combining rate of deposition and line speed), or a measure of the quantity of binder and/or fibers per unit area (by combining the signals received from leads 25a, 53a and 45a). The output on lead 610 may be then fed to comparison circuit 62 where a difference, if any, is detected with respect to the actual measurement as received on lead 60a. Again, the output on lead 62a of a different signal may be utilized to activate an alarm circuit 63. Alternatively, the output on 62a may be utilized to effect a change or modification in the operation of the binder feed control 53, in the conveyor speed control 45, the oven heater control 75, the oven blower control 73, and/or the chopper cycle control 86.

There has thus been described a method of and apparatus for manufacturing fibrous structures or a method of control in which a number of variables may receive preselected set points from a master control, the variables being divided between independent and interrelated variables. One of the interrelated variables, preferably a primary variable, may be utilized to effect a modification of the set point operation of the other interrelated variables in response to a change in the primary variable. Alternatively, any one of the interrelated variables may be utilized to control or effect a change in other interrelated variables. Actual physical measurement of the product being manufactured may be utilized to further double check the operation as well as providing additional modifying signals for the controls involved.

In conclusion, it is apparent that. within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention coinprehending all the variations thereof.

I claim:

1. Apparatus for forming a fibrous structure comprising a fiber deposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon, said fiber providing means including electrically heated bushing means for providing heat-softenable material at attenuating temperature and means for attenuating fibers from said molten material, means for sensing the amount of electrical power supplied to said electrically heated bushing means and providing a power signal proportional thereto, and means responsive to said sensing means for driving said collecting surface means at a speed dependent upon said proportional signal.

2. Apparatus as defined in claim 1 which further includes means responsive to said electrical power sensing means for supplying an additional component to said fibrous structure being formed in an amount dependent upon said proportional signal.

3. Apparatus as defined in claim 1 which further includes means for measuring the weight per unit area of fibers deposited on said collecting surface and providing a measurement signal proportional thereto, and means for comparing said measurement signal with said power signal to check the accuracy of said power signal.

4. Apparatus for forming a fibrous structure comprising a fiber decomposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon, means for sensing the rate of deposition of fibers on said collecting surface means, means responsive to said sensing means for driving said collecting surface means at a speed proportional to the rate of deposition sensed, means for comparing the actual quantity of fibers deposited on said collecting surface means with a predicted quantity of fibers based upon sensed rate of deposition of fibers and collecting surface speed, said comparing means providing a difference signal in response to a predetermined difference between actual and predicted quantities, and means responsive to said difference signal for activating an alarm means.

5. Apparatus for forming a fibrous structure comprising a fiber deposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon,

means for sensing the rate of deposition of fibers on said collecting surface means, means responsive to said sensing means for driving said collecting surface means at a speed proportional to the rate of deposition sensed, means for comparing the actual quantity of fibers deposited on said collecting surface means with a predicted quantity of fibers based upon sensed rate of deposition of fibers and collecting surface speed, said comparing means providing a difference signal in response to a predetermined difference between actual and predicted quantities. and means responsive to said difference signal for modifying the effect of said rate of deposition signal on said collecting surface driving means.

6. Apparatus for forming a fibrous structure comprising a fiber deposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon, means for sensing the rate of deposition of fibers on said collecting surface means, means responsive to said sensing means for driving said collecting surface means at a speed proportional to the rate of deposition sensed, means responsive to said deposition rate sensing means for supplying an additional component to said fibrous structure being formed in an amount proportional to the rate of deposition sensed, means for comparing the actual combined quantity of fibers and said additional component deposited on said collecting surface means with a predicted combined quantity of fibers and additional component, said comparing means providing a difference signal in response to a predetermined difference between actual and predicted quantities, and means responsive to said difference signal for activating an alarm system.

7. Apparatus for forming a fibrous structure comprising a fiber deposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon, means for sensing the rate of deposition of fibers on said collecting surface means, means responsive to said sensing means for driving said collecting surface means at a speed proportional to the rate of deposition sensed, means responsive to said deposition rate sensing means for supplying an additional component to said fibrous structure being formed in an amount proportional to the rate of deposition sensed, means for comparing the actual combined quantity of fibers and said additional component deposited on said collecting surface means with a predicted combined quantity of fibers and additional component, said comparing means providing a difference signal in response to a predetermined difference between actual and predicted quantities, and means responsive to said difference signal for modifying the effect of said rate of deposition on said collecting surface driving means.

8. Apparatus for forming a fibrous structure comprising a fiber deposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon, means for sensing the rate of deposition of fibers on said collecting surface means, means responsive to said sensing means for driving said collecting surface means at a speed proportional to the rate of deposition sensed, means responsive to said deposition rate sensing means for supplying an additional component to said fibrous structure being formed in an amount proportional to the rate of deposition sensed, means for comparing the actual combined quantity of fibers and said additional component deposited on said collecting surface means with a predicted combined quantity of fibers and additional component, said comparing means providing a difference signal in response to a predetermined difference between actual and predicted quantities, and means responsive to said difference signal for modifying the effect of said rate of deposition on said additional component supplying means.

9. Apparatus for forming a fibrous structure comprising a fiber deposition station including a movable collecting surface means and means for providing fibers above said collecting surface means for deposition thereon, means for sensing the rate of deposition of fibers on said collecting surface means, means responsive to said sensing means for driving said collecting surface means at a speed proportional to the rate of deposition sensed, means responsive to said deposition rate sensing means for supplying an additional component to said fibrous structure being formed in an amount proportional to the rate of deposition sensed, means for comparing the actual combined quantity of fibers and said additional component deposited on said collecting surface means with a predicted combined quantity of fibers and additional component, said comparing means providing a difference signal in response to a predetermined difference between actual and predicted quantities, said component being a binder, means responsive to said rate of deposition sensing means for heating and curing said binder by supplying an amount of heat proportional to the rate of deposition sensed, and means responsive to said difference signal for modifying the effect of said rate of deposition on said heating and curing means.

10. Apparatus for manufacturing a glass fiber mat comprising a glass fiber forming station which includes means for melting heat-softenable material and attenuating glass fibers from said molten material, movable collecting surface means arranged to receive fibers from said fiber forming station in a mat-like mass thereon, means for driving said collecting surface past said fiber forming station, master control means for providing a signal to set the speed of said driving means in response to a setting of said master control calculated to produce a predetermined product having a desired thickness of said matlike mass on said moving collecting surface, and means for sensing the amount of heat supplied to keep said molten material at attenuating temperature and providing a temperature signal proportional thereto, said temperature signal being connected to modify the effect of said master control signal on the speed of said driving means.

11. Apparatus for manufacturing a glass fiber mat comprising a glass fiber forming station which includes means for melting heat-softenable material and attenuating glass fibers from said molten material, movable collecting surface means arranged to receive fibers from said fiber forming station in a mat-like mass thereon, means for driving said collecting surface past said fiber forming station, master control means adapted to provide a signal to set the speed of said driving means in response to a setting of said master control calculated to produce a predetermined product having a desired thickness of said mat-like mass on said moving collecting surface, means for sensing the rate of deposition of fibers on said collecting surface and providing a signal proportional thereto, said deposition signal being supplied to said driving means to modify the effect of said master control signal thereon, hood means disposed between said fiber forming station and said collecting surface, said hood means having side walls which are adjustable to define a fiber deposition width on said collecting surface, and means for adjusting said side walls in response to an adjusting signal from said master control derived from the master control setting to produce a desired thickness.

12. Apparatus for manufacturing a glass fiber mat comprising a glass fiber forming station which includes means for melting heat-softenable material and attenuating glass fibers from said molten material, movable collecting surface means arranged to receive fibers from said fiber forming station in a mat-like mass thereon, means for driving said collecting surface past said fiber forming station, master control means adapted to provide a signal to set the speed of said driving means in response to a setting of said master control calculated to produce a predetermined product having a desired thickness of said mat-like mass on said moving collecting surface, means for sensing the rate of deposition of fibers on said collecting surface and providing a signal proportional thereto, said deposition signal being supplied to said driving means to modify the effect of said master control signal thereon, means for adding binder to said mat-like mass, binder control means for said binder adding means responsive to said master control signal to set the rate of binder addition, said binder control means being also responsive to said deposition rate signal to modify the effect of said master control signal thereon.

13. A method of manufacturing a glass fiber mat comprising the steps of moving a collecting surface past a glass fiber providing station, heating glass at said fiber providing station to provide molten glass at a fiber attenuating temperature, attenuating streams of said molten glass into fibers and depositing said fibers on said collecting surface, monitoring the amount of heat supplied to maintain said molten glass at said attenuating temperature and providing a signal which varies in response to the amount of heat supplied, and varying the speed of said collecting surface in response to a change in said signal to obtain a mat-like mass of glass fibers on said collecting surface having a desired weight per unit area.

14. A method as defined in claim 13 which includes the further steps of establishing a set-point speed of said collecting surface based upon a predicted rate of deposition of fibers on said surface, and varying the speed from said set-point in response to a change in said sensed heat signal.

15. A method of manufacturing a glass fiber mat comprising the steps of moving a collecting surface past a glass fiber providing station, depositing glass fibers thereon, sensing the rate of deposition of glass fibers on said collecting surface, varying the speed of said collecting surface in response to the rate of deposition sensed to obtain a mat-like mass of glass fibers on said collecting surface having a desired weight per unit area, providing a set-point speed of said collecting surface based upon a predicted rate of deposition of fibers on said surface, varying the speed from said set-point in response to said sensed rate of deposition, positioning a hood between said fiber providing station and said collecting surface and adjusting the position of side walls of said hood to define the width of fiber deposition on said collecting surface, and varying the speed of said collecting surface in response to said sensed rate of deposition and the adjusted hood width to obtain a desired thickness of fiber deposition.

References Cited UNITED STATES PATENTS 2,888,060 5/1959 Kjell-Berger 659 X 2,913,146 11/1959 Dickerson 198-39 X 3,078,587 2/1963 Huck 34-52 X 3,126,268 3/1964 Roberson 65-11 3,429,681 2/1969 Krakauer et al 654 X 3,430,751 3/1969 Bateson 19839 X 3,437,508 4/1969 Gorski 653 X 3,445,207 5/1969 Gorens 659 X S. LEON BASHORE, Primary Examiner R. L. LINDSAY, 1a., Assistant Examiner US. Cl. X.R. 

